Defucosylation levels (deFuc%) of MAbs produced with different methods to regulate medium osmolality. Open symbols hyperosmotic, cross symbols hypoosmotic, closed symbols constant osmotic conditions. Cells were cultured in a 5-L fed-batch bioreactor with custom-made medium containing low NaCl. Osmolality was adjusted by supplementing with NaCl. a glucose concentration in the medium, b medium osmolality, c deFuc% MAbs harvested on day 11, and d viable cell density. Independent experiments under similar conditions exhibited similar initial results in 1-L bioreactors